P. Parma

Properties of low luminosity radio galaxies: Polarization and jets

A progress report is given on further radio studies of the B2 sample of low luminosity radio galaxies. We present results on the polarization at 20 cm and compare our results with the Laing-Garrington effect. We also discuss new results on the so called naked jets.

Radio Observations of the Marano Field: Sub-Millijansky Source Counts and Spectral Index Studies

The Marano Field (centered at a(2000)=03 h 15 m 09 s , δ(2000)=–55° 13’ 57”) is a deep ROSAT field (flux limit ~ 4 × 10–15 erg cm–2 s–1), which has been entirely covered by ESO 3.6 m plates and in the inner part by deep CCD exposures. In order to follow up these data in other wavelength regions, deep radio observations of this field have been carried out with the Australia Telescope Compact Array (ATCA) at 1.370 and 2.378 GHz. The minimum reached rms noise value is ~42 µJy at both frequencies. 80 and 45 sources form complete samples above 5.5 σ local level at 1.370 and 2.378 GHz respectively, in a square area of ~0.34 sq. deg. Almost all of the sources detected at 2.378 GHz have been detected also at 1.370 GHz.

A Deep 20 cm Radio Mosaic of the ESO Key-project Galaxy Redshift Survey

In two strips of 22° × 1° and 5° × 1° near the SGP Vettolani et al. (1993, IAU Symposium 161, “Astronomy from Wide Field Imaging”, H.T. MacGillivray ed., Reidel, in press) have made a deep redshift survey as an ESO Key Project. All the galaxies down to b J ~ 19.4 were observed with the OPTOPUS multi-fiber spectrograph on the 3.6 m telescope in La Silla, yielding 3348 redshifts. The survey has a typical depth of z = 0.1. It fully samples the optical luminosity function down to B = −15 and various galaxy populations (e.g. normal galaxies, LSBDs and BCDs) are present. Interestingly, emission lines (OII, Hβ, OIII) have been found in a large fraction of the galaxy spectra (~ 40%), suggesting strong evolution of the galaxy population in terms of enhanced star formation.

The Lockman Hole: Radio Identification of Very Faint Rosat Sources

The ROSAT satellite has carried out a very deep X-ray survey of a particular region of the sky, the Lockman Hole, known for its exceptionally low HI column density. The field was also observed at 20 cm with the C configuration of the Very Large Array. We made four observations of three hours each, in different pointing positions, and combined the four resulting images to form one mosaic effectively representing one single 12 hour observation and covering the whole ROSAT field. The radio image has an RMS noise of 29 µJy in the central part, degrading to ~50 µJy at the outer 20 arcmin radius. A complete radio catalogue was constructed: it contains 150 sources with peak flux density e120 µJy. In addition we searched for radio sources with peak flux > 3σ at the positions of X ray sources.